Hello All
 
I have in front of me the Varroa calculator issued by MAFF in the United
Kingdom. I also obtained from Dr Stephen Martin who developed this
calculator, a copy of a paper entitled 'A population model for the
ectoparistic mite varroa jacobsoni in honey bee (Apes mellifera) colonies'
which was used to develop the calculator, and runs to 15 pages. For me at
any rate, the research work has been largely done, and I do not believe that
it is productive at this stage, for us to attempt to engage in figuring out
our own home grown formulae or theories.
 
I quote below some notes on mite monitoring which are printed on the
calculator and which may be found useful. (Obviously these relate to the UK
or to countries having a similar climate).
 
'Before you can use the Varroa calculator to estimate the period before
control measures are required, you must first estimate the number of mites
in the colony. This can be achieved by either measuring the daily mite fall
or infestation level of the bees or sealed brood.'
 
It then goes on to give equations as follows: (Do not let the word
'equation' put you off, this is only simple arithmetic!).
 
'To convert the daily mite drop into estimated number of mites in the colony
use the following equations.
 
( E = estimated number of mites in colony, D = daily mite fall, * is multiply)
 
Nov to Feb:          E = D * 400
May to Aug:          E = D * 30
Mar, Apr, Sept, Oct: E = D * 100. The value of 100 is a rough approximation
and should be used as a guide only.'
 
It will thus be appreciated that the accuracy of the estimated colony mite
count directly relates to the accuracy of the daily mite fall count. And
since the estimated colony mite count is the basis for when (if at all)
treatment is carried out, the accuracy of the daily mite fall count is of
paramount importance.
 
'To convert the bee or sealed brood infestation levels into estimated number
of mites in the colony use the following equations.
 
(* is multiply, / is divide, E = estimated number of mites in colony)
 
For sealed drone brood use:
 
E = Number of drone cells infested / number of drone cells sampled * Total
number of sealed drone cells in colony * 10
 
 
For sealed worker brood use:
 
E = Number of worker cells infested / number of worker cells sampled * Total
number of sealed worker cells in colony * 1.8
 
 
For adult bees in summer use:
 
E = Number of bees infested / number of bees sampled * Total number of bees
in colony * 2.9
 
For adult bees in winter use:
 
E = Number of bees infested / number of bees sampled * Total number of bees
in colony'
 
The following paragraph also appears on the varroa calculator.
 
'The calculator was developed by Dr S Martin of the NBU. For further copies
contact NBU, CSL, Sand Hutton, York YO41 1LZ (UK), or BBKA, NAC, Stoneleigh
Park, Warks CV8 2LZ (UK)'
 
 
I would like to take this opportunity of thanking Madeleine Pym for having
found and told us about Chris Parker's site on varroa. It is an excellent
site and I believe that it should be visited by every beekeeper.
 
Site:
www.airtime.co.uk/beekeeping/apiary/maff.htm
 
 
I have learned a lot from this interchange, and thanks to all who posted
replies to my initial questions regarding the additional benefits of varroa
floors over and above their obvious benefits in combatting varroa.
 
Sincerely
 
Tom Barrett
49 South Park
Foxrock
Dublin 18
Ireland
 
Hobbyist beekeeper
 
e mail [log in to unmask]
Tel + 353 1 289 5269
Fax + 353 1 289 9940
 
Latitude  53 Degrees 16' North
Longitude  6 Degrees  9' West of Greenwich